183 research outputs found
The development of fluorescent protein tracing vectors for multicolor imaging of clinically isolated Staphylococcus aureus
Recent advances in fluorescent protein technology provide a wide variety of biological imaging applications; however current tools for bio-imaging in the Gram-positive bacterium Staphylococcus aureus has necessitated further developments for fluorescence intensity and for a multicolor palette of fluorescent proteins. To enhance the expression of multicolor fluorescent proteins in clinical S. aureus strains, we developed new fluorescent protein expression vectors, containing the blaZ/sodp promoter consisting of the β-lactamase gene (blaZ) promoter and the ribosome binding site (RBS) of superoxide dismutase gene (sod). We found S. aureus-adapted GFP (GFPsa) driven by the blaZ/sodp promoter was highly expressed in the S. aureus laboratory strain RN4220, but not in the clinical strains, MW2 and N315, harboring the endogenous blaI gene, a repressor of the blaZ gene promoter. We therefore constructed a constitutively induced blaZ/sodp promoter (blaZ/sodp(Con)) by introducing substitution mutations into the BlaI binding motif, and this modification allowed enhanced expression of the multicolor GFP variants (GFPsa, EGFP, mEmerald, Citrine, Cerulean, and BFP) as well as codon-optimized reef coral fluorescent proteins (mCherry and AmCyan) in the S. aureus clinical strains. These new fluorescent probes provide new tools to enhance expression of multicolor fluorescent proteins and facilitate clear visualization of clinical S. aureus strains.This study was supported by Grant-in-Aid for Young Scientists (B) Grant Number JP25861744 and Grant-in-Aid for Scientific Research (C) Grant Number JP25460533 from the Japan Society for the promotion of Science (JSPS). A confocal laser scanning microscopy was performed at the Analysis Center of Life Science, Natural Science Center for Basic Research and Development, Hiroshima University
Possible direct method to determine the radius of a star from the spectrum of gravitational wave signals
We computed the spectrum of gravitational waves from a dust disk star of
radius R inspiraling into a Kerr black hole of mass M and specific angular
momentum a. We found that when R is much larger than the wave length of the
quasinormal mode, the spectrum has several peaks and the separation of peaks
is proportional to irrespective of M and a. This
suggests that the radius of the star in coalescing binary black hole - star
systems may be determined directly from the observed spectrum of gravitational
wave. This also suggests that the spectrum of the radiation may give us
important information in gravitational wave astronomy as in optical astronomy.Comment: 4 pages with 3 eps figures, revtex.sty, accepted for publication in
Phys. Rev. Let
Magnetic Instability of Pr3Ru4Sn13
We report on the quantum criticality of PrRuSn revealed by our
new material research. PrRuSn has been synthesized by flux
growth and characterized by single X-ray, powder X-ray, and powder neutron
diffraction measurements. The compound adopts a YbRhSn-type
structure with a cubic Pmn. From the magnetization at 1 T, the
effective magnetic moment was estimated to be 3.58 per Pr,
suggesting that the magnetism is mainly contributed by Pr ions. The
specific heat and magnetization show an anomaly at ~ K owing to
the phase transition. The muon spin rotation and relaxation (SR) time
spectra exhibit clear oscillations below . This suggests that the phase is
magnetically ordered. The volume fraction of the magnetic phase estimated from
the initial asymmetry is around ten percent. In addition, spin fluctuations
were observed at low temperatures. These results provide microscopic evidence
that the material is closest to the antiferromagnetically quantum critical
point with a partial order among PrSn ( Co, Ru, Rh).Comment: 14 pages, 4 figures, accepted for publication in J. Phys. Soc. Jp
AN EVALUATION OF PERFORMANCE OF A DOUBLE-LEG CIRCLE ON A POMMEL HORSE, AND A DESIRABLE PERFOMANCE PROPOSAL
For the evaluation of the performance of a double-leg circle on a pommel horse, we focused on the relation between the horizontal rotation of a body about the vertical axis in the center of a pommel horse and the hip rotation about the longitudinal axis of a body. Several gymnasts having different levels of skill were examined by using a motion capture system. The analysis shows that the horizontal rotation and the hip rotation are in good synchronization for the performance of a well-trained gymnast
Sustained Increase in the Incidence of Acute Decompensated Heart Failure After the 2011 Japan Earthquake and Tsunami
This study investigated the long-term impact of the 2011 Japan earthquake and tsunami on the incidence of acute decompensated heart failure (HF) in the disaster area. This was a population-based study using comprehensive registration for all hospitals within the study area. The standardized incidence ratio (SIR) and 95% confidence interval (CI) for new onset of HF during the disaster year (2011) and postdisaster years (2012 to 2014) were determined. When SIR were compared between the low- and high-impact areas, as defined by the extent of tsunami inundation in residential areas, SIR showed a significant increase in high-impact areas in 2011 (1.67, 95% CI 1.45 to 1.88) and tended to return to baseline in 2012, the first postdisaster year (1.25, 95% CI 1.06 to 1.43). The rate again increased in 2013 (1.38, 95% CI 1.18 to 1.57) and 2014 (1.55, 95% CI 1.35 to 1.75). In low-impact areas, no such increase was apparent during either the disaster year or the postdisaster years. Mean postdisaster period SIR for municipalities significantly correlated with the percentage of tsunami flooding in residential areas (r = 0.52, p <0.05) and with the percentage of refugees within the population (r = 0.74, p <0.01). There was no significant relation between maximum seismic intensity and mean SIR in these municipalities. In conclusion, these results suggest that the catastrophic tsunami but not the earthquake per se resulted in a prolonged increase in the incidence of HF among the general population living in tsunami-stricken areas
Gravitational Waves in Brans-Dicke Theory : Analysis by Test Particles around a Kerr Black Hole
Analyzing test particles falling into a Kerr black hole, we study
gravitational waves in Brans-Dicke theory of gravity. First we consider a test
particle plunging with a constant azimuthal angle into a rotating black hole
and calculate the waveform and emitted energy of both scalar and tensor modes
of gravitational radiation. We find that the waveform as well as the energy of
the scalar gravitational waves weakly depends on the rotation parameter of
black hole and on the azimuthal angle.
Secondly, using a model of a non-spherical dust shell of test particles
falling into a Kerr black hole, we study when the scalar modes dominate. When a
black hole is rotating, the tensor modes do not vanish even for a ``spherically
symmetric" shell, instead a slightly oblate shell minimizes their energy but
with non-zero finite value, which depends on Kerr parameter . As a result,
we find that the scalar modes dominate only for highly spherical collapse, but
they never exceed the tensor modes unless the Brans-Dicke parameter
\omega_{BD} \lsim 750 for or unless \omega_{BD} \lsim 20,000
for , where is mass of black hole.
We conclude that the scalar gravitational waves with \omega_{BD} \lsim
several thousands do not dominate except for very limited situations
(observation from the face-on direction of a test particle falling into a
Schwarzschild black hole or highly spherical dust shell collapse into a Kerr
black hole). Therefore observation of polarization is also required when we
determine the theory of gravity by the observation of gravitational waves.Comment: 24 pages, revtex, 18 figures are attached with ps file
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